Breathing mask and a sealing lip device for a breathing mask

ABSTRACT

An elastomeric cushion for a breathing mask is configured for sealed delivery of a flow of breathable gas at a positive pressure with respect to ambient air pressure to an entrance of a patient&#39;s airways including at least an entrance of the patient&#39;s nares. The elastomeric cushion includes a sealing lip with an elastomeric wall configured to form a seal with the patient&#39;s face. An elastomeric wall thickness of the sealing lip is varied so that when the sealing lip sealingly engages the patient&#39;s face, a portion of the seal at the patient&#39;s nose bridge is formed by a relatively thin-walled portion of the sealing lip and other portions of the seal are formed by relatively thick portions of the sealing lip.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/566,115, filed Dec. 10, 2014, now allowed, which is a continuation ofU.S. application Ser. No. 12/320,484 filed Jan. 27, 2009, now U.S. Pat.No. 8,931,484, which is a continuation of U.S. application Ser. No.10/220,018, filed Aug. 26, 2002, now U.S. Pat. No. 7,827,990, which isthe U.S. National Phase of International Application PCT/EP00/01586,filed Feb. 25, 2000, which designated the U.S. and that InternationalApplication was not published under PCT Article 21(2) in English, theentire contents of each of which are incorporated herein by reference.

BACKGROUND AND SUMMARY

The invention concerns a sealing lip device for a breathing mask, abreathing mask per se and a method and a mold for producing same.

In particular the invention concerns breathing masks which can be fittedto the nose region in sealing relationship and which have a sealingdevice extending in the region of the upper lip of the mask wearerbetween the mouth and the nose. Breathing masks are used in particularin the medical and technical areas for the feed of a respiratory gas, inparticular under an increased pressure.

In those breathing masks, a seal in relation to the surface of the faceof a wearer is usually achieved by a peripherally extending sealing lipmade from an elastomeric material.

The sealing action achieved with a sealing lip of that kind generallyincreases with the pressure with which the sealing lip is pressedagainst the surface of the face. However the level of wearing comfort isadversely affected by comparatively high contact pressures. Depending onthe respective sensitivity of the mask wearer long-term use of the knownbreathing masks gives rise to troubles.

The object of the present invention is to provide a breathing mask inwhich a high level of sealing action can be reliably achieved, with ahigh degree of wearing comfort.

In accordance with the invention that object is attained by a sealinglip device for a breathing mask having a receiving opening for receivingat least the nose tip region of a mask wearer, a sealing lip which isformed from an elastomeric material and which surrounds the receivingopening and which crosses the bridge of the nose in the applicationposition and which has a contact zone provided for bearing against theface of a mask wearer, wherein the sealing lip is elastically yieldinglyarranged in such a way that in the region of the bridge of the nosethere is a higher degree of flexibility than in the region of thenostrils and/or the upper lip.

That advantageously affords a high degree of compatibility with the mostwidely varying facial architectures, with a high level of wearingcomfort. The breathing mask according to the invention is distinguishedin particular in the region of the bridge of the nose by a high degreeof sealing integrity, without considerable pressures in relation tosurface area occurring in that respect. The high level of sealing effectachieved in the region of the bridge of the nose effectively obviates inparticular eye irritation effects and feeling the effects of drafts.

In accordance with a particularly preferred embodiment of the inventionthe defined flexibility of the sealing lip zone which fits on the regionof the bridge of the nose is achieved by the sealing lip device beingsuspended in the region of that zone on a bellow structure. That bellowsstructure is preferably dimensioned in such a way that it forms anabutment device, upon suitably deep penetration of the bridge of thenose. The abutment surfaces which come into effect there are preferablysuch that they form a comparatively large contact area, at the latest inthe inwardly resiliently deflected condition, so that even when thebellows structure becomes operative in the resiliently inwardlydeflected condition, the arrangement does not involve any unacceptablyhigh pressures in relation to surface area.

In a particularly advantage fashion, a hinge characteristic which isdefined by different wall thicknesses is imparted to the bellowsstructure. Preferably the bend or hinge location is of a comparativelythin-gauge nature, whereas the zones which are disposed therebetween areslightly thicker. As an alternative thereto or also in combination withthat measure, it is also possible to provide rolling bellows structures,by virtue of suitable wall thicknesses.

In a particularly advantageous manner the bellows structure has aplurality of fold indentations. Preferably at least one fold indentationextends from the region of the bridge of the nose into a region adjacentto the nostrils in the position of use of the mask.

Particularly when the structure has a plurality of fold indentationspreferably at least one thereof extends around the entire periphery ofthe sealing lip device. The spring characteristic of the respective foldindentation can be definedly established for given peripheral zones insuch a way that there is a higher level of flexibility in the region ofthe bridge of the nose and there is a lower level of flexibility in theregion of the upper lip or in particular in the region of the nostrils.(Those orientations are with reference to the application position ofthe mask).

Particularly when using the bellows structure in the sealing zone regionof the bridge of the nose, the sealing device is preferably designed insuch a way that the flexibility of the sealing lip, which is in oppositerelationship to the application direction, is so matched that there isan adaptation or articulation axis in the nostril or upper lip region.That makes it possible for the corresponding breathing mask to be fittedto the face of the mask wearer predominantly in the region of the zonesof the face which are adjacent to the nostrils and on the upper lip, inwhich respect the preferably extremely thin-wall sealing lip zone whichis provided for sealing at the bridge of the nose can be pivoted withrespect to the mask frame, in accordance with the facial architecture.By virtue of the internal pressure obtaining in the mask, that pivotablysupported sealing lip zone can then be uniformly pressed against thebridge of the nose of the wearer of the mask, without in that situationthe occurrence of surface pressures which considerably exceed theinternal pressure of the mask.

The particularly advantageous kinematics and hinge characteristic of themask cushion or pad formed by the sealing lip device can in particularbe achieved by local zones with a higher load-bearing capability beingprovided in the region of the sealing lip, which is adjacent to thenostrils or the upper lip.

In accordance with a particularly preferred embodiment of the inventionthe zones of higher load-bearing capability are formed by locallythickened zones of the sealing lip. The transition of the locallythickened zones is preferably effected along regions in the manner ofthe edge of a lens, or also in a shallowly terminating configuration,possibly without the transition between the zones being clearlyperceptible.

In accordance with a particularly preferred embodiment of the inventionthe locally thickened zones are supported on a mask frame zone by way ofa support structure which is formed in the sealing lip. That mask framezone is preferably of a thick-wall nature and in that respect involves awall thickness in the range of between 3 and 6 mm.

The zones of higher load-bearing capability are preferably of a pad-likenature, as is shown by way of example in FIG. 1 to which reference willbe subsequently made in greater detail.

A form of support for the mask pad, which is particularly advantageousfrom ergonomic points of view is achieved if the zones of higherload-bearing capability, in the region of the face-contact zone, areeach of a substantially crescent moon-shaped configuration. The limbs ofthose zones of higher load-bearing capability, which are provided in theregion for bearing against the upper lip, are preferably of a shortenedconfiguration in such a way that a zone of high elasticity andflexibility in opposite relationship to the application direction isprovided in the region of the upper lip between the zones of higherload-bearing capability. That higher degree of flexibility canadvantageously be achieved by also providing here a local fold structureor a correspondingly thin-walled zone.

In accordance with a particularly preferred embodiment of the inventionthe sealing lip device is mounted to a mask base body. The mask basebody can also be formed from an elastomeric material, for examplesilicone rubber. In accordance with a particularly preferred embodimentof the invention however the mask base body is formed by a hard shell,for example comprising a fully transparent material. The hard shellpreferably has a conduit connection facing in the application positiontowards the forehead region of the mask wearer. As an alternativethereto it is also possible for the hard shell to be provided with acentral or lateral connecting structure for coupling a respiratory gasconduit.

Mounting the sealing lip device or the sealing pad to the hard shell ora mask base body is preferably effected by using a coupling structure.In accordance with a particularly preferred embodiment of the inventionthat coupling structure comprises, on the part of the hard shell, aperipheral bead portion and, on the part of the sealing lip device, aframe portion with a complementary receiving groove. The groove and thebead are preferably such that in the case of an expansion of the maskpad, caused by mask internal pressure, in the region of the couplingstructure, there are surface pressures which are always higher than theinternal pressure in the mask. That provides for a particularly reliablesealing action, without the addition of adhesives.

In a particularly advantageous fashion, there are provided means forfixing the position of the sealing lip device with respect to the hardshell in the peripheral direction. Those means can be formed for exampleby positioning projections or in particular by apertures in theperipheral bead.

A prestressing is preferably imparted to the sealing lip device, whichprestressing is advantageously achieved by elastic deformation uponcoupling to the hard shell. That makes it possible to definedlyinfluence the deformation characteristics of the sealing lip device. Inparticular it is possible to prestress given zones of the sealing lipdevice in such a way that the formation of wrinkle folds in the regionof the face-sealing zone is advantageously precluded.

In accordance with an advantageous embodiment of the invention the frameportion is such that it extends substantially in one plane. That permitsthe hard shell to be of a comparatively flat structure and allows themask pad to be prestressed in a simple fashion.

As an alternative thereto however it is also possible for the maskarrangement to be designed in such a way that the frame portion is of aconfiguration which advances in the region of the articulation axisrelative to the zone of high load-bearing capability. That makes itpossible to already impart to the hard shell itself a configurationwhich substantially corresponds to the statistically most probablefacial architecture.

Advantageously the wall thickness of the thin zone is in the range ofbetween 0.65 and 1.85 mm. That wall thickness imparts to the mask aresistance to pressure which is sufficient even in the case of maskpressures in the region of 15 mbars.

The wall thickness of the zone of high load-bearing capability ispreferably in the range of between 0.80 and 4 mm.

In accordance with a particularly preferred embodiment of the inventionthe mask pad is produced by a multi-stage mold cavity filling method.That makes it possible to impart to the zone of high load-bearingcapability, a coloring which differs from the zone of low load-bearingcapability. It is also possible to definedly match the mechanicalproperties of the materials respectively used for the respective zone.

The zone of high load-bearing capability is preferably formed by twoelastomeric portions which project up from the lower corner region ofthe frame portion and which pass out into the sealing lip in the form offlat limbs. The sealing lip itself is preferably formed from anelastomeric material, in particular fully transparent silicone rubber.The outside surface of the mask pad, which comes directly into contactwith the face of the mask wearer, is preferably of a velvety mattfinish. That affords an improved feel when wearing the mask.

An embodiment of the invention which is particularly advantageous frommanufacturing procedure points of view is afforded if the hard shell isinjection molded to the sealing lip device. Besides particularlyreliable coupling of the hard shell or the mask base body and the maskpad, that also precludes the formation of a gap, which isdisadvantageous from bacteriological points of view.

In regard to a method of producing a sealing lip device for a breathingmask, the above-specified object is attained by an elastomeric materialbeing introduced into a mold cavity formed by a mold, at least partiallysetting in the mold cavity, and being removed from the mold afteropening thereof, wherein the elastomeric material is introduced into thecorresponding mold cavity in two steps which occur in succession intime.

In that way it is possible to provide a mask pad which has a singlesealing lip which in the application direction affords flexibility whichis defined in accordance with the load-bearing capability and thestatistically expected architectural variance of the corresponding zoneof the face.

Advantageously, a carrier structure of the sealing lip device and athin-wall zone of the sealing lip are formed in steps which are separatein terms of time, and possibly using materials involving differentmechanical properties and possibly color.

Preferably the carrier structure is formed in a first injection step andthe thin-wall zone is formed in a subsequent second injection step. Theoperation of introducing the respective material is preferably effectedby injection or beforehand by suitably introducing same into the moldcavity to fill it.

The mold cavity which is provided for filling with the material formingthe thin-wall zone is preferably defined by a mold which delimits theoutside of a sealing lip being lifted off a core which delimits theinside of the sealing lip.

As an alternative thereto it is also possible for the carrier structureto be formed by a mold cavity which is defined by a core delimiting theinside of a sealing lip and an outer mold, wherein to form the thin-wallzone of the sealing lip the outer mold is changed and then the materialfor forming the thin zone is introduced into the mold cavity which isnow present and which is intended for the thin-wall zone, and setstherein.

In the mold aspect of the invention, the above-specified object isattained by a mold for producing a sealing lip device for a breathingmask, comprising a mold core device which in conjunction with an outermold defines a mold cavity having a fold portion.

It is advantageously possible in that way to produce the sealing lipdevice for example in the context of a fully automated siliconeinjection molding method.

In accordance with a particularly preferred embodiment of the inventionthe outer mold is of a multi-part nature. Preferably the outer moldcomprises a mold half which delimits the outside surface of the sealinglip and a mold half which co-operates with said mold half and whichdelimits the rest of the region of the outside surface of the sealingpad. The inner region of the sealing pad is delimited by a preferablyintegral core device. With the described two-part embodiment of theouter mold, it is possible for an outer mold half to be withdrawn alonga mold-opening axis which extends in a direction in oppositerelationship to the side at the bridge of the nose or a direction remotefrom the upper lip sealing zone. The bellows zone which is locallyprovided in the region of the bridge of the nose and the mold-openingaxis as well as the configuration of the coupling frame of the mask padare preferably matched in such a way as to afford mold-opening angles atleast in the region of 2°.

In particular in this case the outside of the sealing lip, which istowards the mask wearer, is preferably formed by an outer mold portionin conjunction with the mold core device, wherein the outer mold portionhas a peripherally extending mold cavity channel which defines theoutside of the sealing lip.

The outer separation edge of the mold cavity channel preferably extendsin the region of the outer peripheral edge of the sealing lip. Thatadvantageously avoids any burrs in the region of the face-contactsurfaces.

In accordance with a particular aspect of the invention, an embodiment,which can be particularly advantageously implemented from productionprocedure points of view, of a leakage device for the discharge of atleast partially consumed respiratory air into the ambient atmosphere isafforded by a breathing mask having a mask body and sealing pad devicewhich is formed from an elastomeric material and which in conjunctionwith the mask body delimits a mask internal space and an outlet devicefor the discharge of at least partially consumed respiratory gas out ofthe mask internal space, wherein the outlet device has a flow pathportion which is at least partially defined by the sealing pad device.

This measure can also be used independently of the above-describeddesign configurations. Advantageous developments of this combination ofthe invention, which is independent per se, are set forth in theappendant claims.

Further advantageous configurations of the invention are recited in theappendant claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Further details of the invention will be apparent from the descriptionhereinafter with reference to the drawing in which:

FIG. 1a shows a perspective view of a mask pad in accordance with afirst embodiment of the invention with a local bellows structure andpad-like zones of increased load-bearing capability in the region of thesealing lips adjacent to the nostrils in the application position,

FIGS. 1b, 1c and 1d provide illustration and accompanying explanationfor the perspective view of FIG. 1 a,

FIG. 2a shows a simplified side view of a further breathing mask with afold indentation and a frame portion extending substantially in oneplane

FIG. 2b shows a simplified side view of a further breathing mask with arolling bellows and a frame portion extending substantially in oneplane,

FIG. 3a shows a simplified side view of a further embodiment of a maskpad, also with a bellows-like fold indentation and an indicatedadaptation or articulation axis,

FIG. 3b shows a simplified side view of a further embodiment of abreathing mask with a fold provided only in the rear third of the maskpad,

FIG. 4 shows a simplified plan view of a sealing lip and diagrams forqualitative illustration of preferred matching of the load-bearingcapability of the sealing lip,

FIG. 5a shows a view in section to describe a preferred embodiment of afold region with a hinge characteristic established by zones ofdiffering wall thicknesses,

FIG. 5b shows an enlarged view of a portion of the sectional viewillustrated in FIG. 5 a,

FIG. 5c is a diagrammatic sketch showing the mechanics of themicrosealing lip structure of FIG. 5 a,

FIGS. 6, 6 a, 6 b, 6 c, 6 d, 6 e, 6 f, and 6 g show diagrammatic viewsto describe preferred cross-sectional configurations in the case of asealing lip device according to the invention,

FIG. 7 shows a diagrammatic view to describe the flexibility of thehinge-like suspension for a sealing lip,

FIG. 8 shows a diagrammatic view to describe a preferred measure forfixing the mask pad in the peripheral direction,

FIG. 9 shows a further diagrammatic view to describe a preferredstructure of a mold in conjunction with advantageous configurations of amask base body (hard shell),

FIG. 10 shows a simplified view in section to describe a fold portionwith a plurality of fold indentations and a defined hingecharacteristic,

FIG. 11 shows a perspective view of a further preferred embodiment of abreathing mask with a mask sealing pad provided with a local bellowsstructure,

FIG. 12 shows a perspective view of the breathing mask of FIG. 11 frombelow,

FIG. 13 shows a simplified view in section through the sealing devicewhich is disposed on the upper lip, to describe the substantiallysmooth-wall transition of the sealing lip into the hard shell mask body,

FIG. 14a shows a simplified view in section through a sealing lip withintegrated leakage opening,

FIG. 14b shows a simplified view in section through a sealing lip withintegrated leakage opening, but with a flow path partially delimited bythe mask frame,

FIG. 14c shows a simplified view in section through a sealing lip withintegrated leakage opening, with a flow path which is formed in the maskframe and which passes into the sealing lip frame portion,

FIG. 14d shows a simplified view in section through a sealing lip withintegrated leakage opening, but with mutually aligned passages in thehard shell and the sealing lip device,

FIG. 14e shows a simplified view in section through a sealing lip withintegrated leakage opening, but with a portion which is extendedupwardly in a bib-like configuration from the interior to a throughopening, and with a through opening formed therein,

FIG. 14f shows a side perspective view of the sealing pad device of FIG.14 b,

FIGS. 15a, 15b, 15c, and 15d show simplified diagrammatic views ofpreferred cross-sections of the flow paths, and

FIG. 16 shows a simplified diagrammatic view in principle to describepreferred leakage zones.

DETAILED DESCRIPTION OF THE INVENTION

The sealing lip device which is shown in FIG. 1a and which is in theform of a mask cushion or pad 1 is made from an elastomeric material,here transparent silicone rubber.

The mask pad 1 includes a sealing lip 3 which extends around the nosereceiving opening 2. The sealing lip 3 has an outer surface which iscurved convexly in the embodiment illustrated here.

The sealing lip 3 is of such an arrangement and configuration that ithas, of itself, zones of differing load-bearing capability. In theembodiment illustrated here that is achieved by suspension, which isflexible in opposite relationship to the application direction Z, of thesealing lip zone a provided for bearing against the bridge of the nose(see FIG. 1b ).

In addition thereto, in the region of the zone b1, b2 (FIG. 1b )adjacent to the nostrils, the sealing lip 3 is of such a configurationthat here it is of a higher load-bearing capability. That provides forpivotability of the mask pad about an adaptation axis X, which extendstransversely through the mask pad in the region identified in FIG. 1b bythe letter e.

The higher load-bearing capability is achieved here by zones 4 which arethickened in a pad-like manner and which here advantageously run intothe sealing lip 3 in a crescent moon-like configuration. The zones 4 ofhigher load-bearing capability are respectively supported at a supportwall portion 5 which is also comparatively thick-walled. The supportwall portions 5 also form an integral component part of the mask pad 1and are embodied in the form of thick-wall zones of the front peripheralwall which extends in the zones b1, c and b2.

The degree of flexibility in opposite relationship to the applicationdirection decreases along the sealing lip 3, starting from the zones 4of high load-bearing capability, to the zenith Q at the side at thebridge of the nose, and then slowly rises to the outer edge point R.

In the illustrated embodiment, the mounting of the zone a of the sealinglip 3, which is yielding in opposite relationship to the applicationdirection Z, is achieved by means of a folding bellows structure ofdiffering load-bearing capability.

The differing load-bearing capability is achieved here both by thegeometry and arrangement of the bellows structure and also by aparticular wall thickness configuration. That wall thicknessconfiguration will be discussed in greater detail hereinafter inparticular with reference to FIGS. 5a -6 g.

The mask pad 1 further includes a peripherally extending frame 8provided with a fixing profile means which is of a complementaryconfiguration to a fixing profile portion provided on a mask base body(not shown).

The peripheral length of the frame 8 and the configuration thereofaround a central axis z of the mask pad 1 are selected in such a waythat, in conjunction with a mask base body, the arrangement provides fordefined prestressing of the mask pad 1, in particular a tendency towardsforward curvature in an outward direction.

In the illustrated embodiment the wall thickness of the sealing lip 3 isin the range of between 0.6 and 3.2 mm.

The configuration of the peripheral edge u which borders the nosereceiving opening 2 is selected in such a way that there are formed twosegments s1, s2 (FIG. 1d ) which project inwardly slightly relative tothe axis z of the mask.

By virtue of the configuration of the peripheral edge u being matched tothe convex curvature of the sealing lip 3, it is possible to achieve adeformation characteristic with which an expansion of the sealing lip 3in the region of the peripheral edge results in a definedly increasedsurface pressure against the face of the wearer of the mask.

Provided in a front end center region c is a further zone of reducedload-bearing capability. That definedly reduced load-bearing capabilityis afforded here by a markedly reduced wall thickness. It is alsopossible to provide local folding bellows structures or rolling bellowsstructures in the zone c.

A particularly preferred embodiment of a sealing lip device is affordedby virtue of the fact that integrated into the same are outlet openings50, by way of which a defined flow of gas can flow away out of theinterior (or plenum chamber) of the breathing mask. Those outletopenings are preferably of an outwardly conically taperingcross-section, as shown in FIG. 1 c.

Preferably, those outlet openings are initially closed for example by athin film and are then opened as required for example by puncturing witha needle. As can further be seen from this sketch the mask pad 1 can bemounted to a mask base body 12 by way of a frame portion 8. For thatpurpose the arrangement preferably has a peripheral bead structure of acrochet needle-like cross-section and with rounded edges.

FIGS. 2a and 2b show side views of further embodiments of a mask pad 1.In those views, the frame 8 extends substantially in a flatframe-defining plane f.

The mask pad 1 also has in the sealing region of the bridge of the nosea local folding bellows structure 9 which provides for flexiblesuspension of the sealing lip 3.

A fold indentation 10 is also provided in the front region c (definitionsimilar to the FIG. 1b ). The arrangement afforded in that way definesan adaptation and articulation axis X or an instantaneous center ofrotation about which the sealing lip 3 can be elastically tilted. Thearrangement here is such that tilt angles α in a range of up to 15° arepossible. Besides the tilting movement itself the sealing lip 3 can alsoexperience individual deformation, corresponding to the facialarchitecture. In particular the peripheral edge u of the nose receivingopening is stretched.

When relatively large tilt angles are involved, here the bellowsstructure becomes effective as an abutment device and limits in an alsoelastically yielding manner further engagement of the bridge of the noseinto the mask pad 1.

The bellows structure 9 has the greatest indentation depth t in theregion of the end which is towards the bridge of the nose. Thatindentation depth t gradually decreases to the front end E of thebellows structure 9.

In the embodiment illustrated here, the end of the bellows structure 9is of a rounded configuration. Advantageously, provided in the region ofthe front end E of the fold indentation is a microfold structure e whichprovides for a more uniform reduction in stresses in the material inthat region. That affords improved durability.

FIG. 3a shows a further embodiment of a mask pad 1 in conjunction with amask body 12 which is only indicated.

This embodiment also has a local folding bellows structure 9. Thegeometry of this bellows structure 9 is so selected that the fold flanks9 a, 9 b extend inclinedly relative to each other. Overall in this casealso the indentation depth t in the region of the end towards the bridgeof the nose is larger than in the other regions. The mask pad 1 alsodefines an adaptation axis X which extends in the region of the zonesc1, b2 and c at the level of the nostrils of the wearer of the mask.

The mask pad 1 also has a higher degree of flexibility in oppositerelationship to the application direction Z by virtue of the suspensionarrangement provided here for suspending the sealing lip 3 at a localbellows structure 9, in the region of the zone a which seals off thebridge of the nose.

FIG. 3b shows a further view of a breathing mask with a mask pad 1according to the invention. The mask pad 1 is here fixed by way of aframe 8 to a mask base body 12. A bellows structure 9 is provided herein the region of the portion of the sealing lip 3 which seals off thebridge of the nose. In a departure from the above-described embodimentsin this case also the peripheral wall of the mask pad is also ofthin-wall configuration in the region of the bellows structure 9. Themask pad 1 is stretched onto the mask base body 12 with considerableexpansion and stretching of the frame 8.

FIG. 4, in conjunction with a plan view onto a half of the sealing lip3, illustrates the load-bearing capability and the flexibility of themask pad 1.

The lowest level of flexibility E of the mask pad 1 obtains in theregion b. The highest level of flexibility obtains in the region a whichcovers over the bridge of the nose and the upper side flanks of the noseof the mask wearer. Obtaining in the region c in addition to theflexibility in opposite relationship to the application direction Zthere is also a relatively high level of flexibility in the radialdirection.

The adaptation axis A extends through the zone b of relatively highload-bearing capability. When a predetermined depth of penetration intothe mask pad 1 is exceeded, the bellows structure becomes operative in aregion d as an abutment device and in that case causes a rapid rise inthe pressure force F transmitted by way of the sealing lip 3, as isindicated by the dash-dotted line portion fl.

The particular mechanical properties of the suspension arrangement forthe sealing lip 3 are preferably determined by the wall thickness in theregion of the bellows structure 9 and by the indentation depth and theorientation of the bellows flanks 9 a, 9 b (FIG. 3a ).

FIGS. 5a and 5c show a preferred configuration of the wall thicknessesof the bellows structure 9. The mask pad 1 is fixed to a mask base body12 in this case by way of a rounded profile structure 12 a which extendsalong the frame 8. In the illustrated embodiment that profile structure12 a is of a crochet needle-like cross-section. Provided at least in aportion-wise manner in the region of the contact zone between the frame8 and the mask base body 12 are peripherally extending profile legs 15which, even in the case of a considerable relative movement, provide asecure sealing action.

Beneath the frame 8 there is initially a thick-wall portion 16 whichgradually reduces to a first bellows hinge location or vertex 17. Thatbellows hinge location or vertex 17 is adjoined by a first bellows flanklimb 9 b. That bellows flank limb 9 b has in cross-section zones ofdiffering wall thickness and extends to a bellows inner hinge location18 defined by a thin-walled zone. The variable wall thickness of theflank limb 9 b forms an indentation region or thin wall portion 77 thatpromotes a hinged motion around the hinge location or vertex 17 (seeFIG. 5a ).

The bellows inner hinge location or vertex 18 is in turn adjoined by asecond bellows flank limb 9 a which also has zones of differing wallthickness. The variable wall thickness of the flank limb 9 a formsanother internal indentation region or thin wall portion 78 thatpromotes a hinged motion around the hinge location or vertex 18.

Finally, the sealing lip 3 is suspended on the second bellows flank limb9 a at a vertex 79. The sealing lip 3 is here extremely thin-walled incomparison with the bellows structure 9.

The sealing pad cross-section illustrated here corresponds inqualitative terms to the sealing pad cross-section in the region of thezone identified as a1 in FIG. 4.

In the course of applying the mask pad to the face of a mask wearer, thesealing lip 3 firstly bears against the face. The bellows flank limbs 9a, 9 b are then deflected resiliently inwardly, corresponding to thedepth of engagement of the bridge of the nose, as illustrated by thearrows P1 and P2. In the case of particularly deep engagement of thebridge of the nose the inner surface of the sealing lip 3 possibly comesinto contract in the region of the zone k with the inside surface, whichfaces theretowards, of the bellows flank limb 9 b. The bellows flanklimb 9 b in turn can bear on the outside surface, which facestheretowards, of the bellows flank limb 9 a.

The kinematics of the sealing pad suspension configuration will be clearby reference to FIG. 5c . Thus the frame can be viewed as a fixedsuspension means K1 at which the bellows flank limb 9 b is mountedpivotably at the hinge location or vertex 17. The inherent elasticity ofthe elastomeric material in the region of the hinge location or vertex17 is symbolically indicated by the spring F1.

The bellows inner hinge location or vertex 18 also involves aninherently elastic characteristic which is indicated by the spring F2.The loose mounting K2 and the spring F3 are due to the fact that thisinvolves a spatial, ring-like structure which also carries forces in theradial direction.

The hinge location or vertex 18 is adjoined by the bellows flank limb 9a and the same is adjoined by the diaphragm-like sealing lip 3.

As illustrated in FIG. 5b , provided along the inner peripheral edge uis a microsealing lip structure by which a sealing edge which terminatesin a thin configuration is slightly prestressed outwardly. Themicrosealing lip structure has a bead portion 19 which increases theresistance to tearing of the sealing lip 3.

The mechanics of this microsealing lip structure is indicated in FIG. 5cby a spring F4 and a hinge location 20. The sealing lip which iselastically suspended in that way, as indicated by the small arrows, canbe urged, flexibly against the surface of the face of the mask wearer,as a consequence of the internal pressure obtaining in the interior (orplenum chamber) of the mask.

As can be seen from FIG. 6 the mask pad 1 is preferably of differingcross-sections along its configuration around the axis Z of the mask, asis diagrammatically indicated here.

The cross-section illustrated in FIG. 6a has a marked hingecharacteristic with abutment properties.

The cross-section illustrated in FIG. 6b already has a lower hingecharacteristic and a smaller fold indentation.

In the regions of the cross-sections illustrated in FIGS. 6c and 6d thebellows property decreases still further.

The higher load-bearing capability of the cross-sections illustrated inFIGS. 6d and 6e is achieved by local thickenings R1, R2 which extendlens-like into the sealing lip. In the zones of high load-bearingcapability, it is possible to forego the bellows structure, as hashappened here.

The alternative cross-sections illustrated in FIGS. 6f and 6g are suchthat there is flexibility in the directions r1 and r2 indicated here.That affords improved adaptability, in terms of the upper liparchitecture, immediately beside the load-bearing zones.

It is also possible for the bellows structure 9 to be of a thin-wallnature. The kinematics of a structure of that kind is diagrammaticallyshown in FIG. 7. The diaphragm-like sealing lip 3 is here suspended ontwo limbs (bellows flank limb 9 a, 9 b). This embodiment, even with lowinternal pressures in the mask, guarantees a high level of adaptability.The elasticity characteristics are illustrated, with reference to a unitforce, for all loading angles, by the polar diagrams II1, II2 which arediagrammatically shown here. As can be seen, a defined degree ofadaptability is afforded by the suspension arrangement according to theinvention for the sealing lip 3, not only in opposite relationship tothe application direction Z but also in all other directions. Thelocation vectors π1, π2, π3 and π4 clearly show that flexibility in theregion of the bellows inner hinge location or vertex 18. The mobilityoptions of the bellows inner hinge location or vertex 18 are alsotransmitted (under the influence of the mask pad peripheral forces) tothe suspension region of the sealing lip 3.

FIG. 8 diagrammatically shows a profile structure 21 which is providedin respect of a mask base body 12 and which advantageously provides forreliable fixing of the mask pad in the peripheral direction. Theillustrated embodiment for that purpose has a plurality of individualfixing projections 22 along the periphery of the mask base body 12. Asan alternative thereto or also in combination with that measure, it isalso possible to provide further fixing means, in particular peg-likeprojections.

FIG. 9 shows in greatly simplified form the structure of a mold forproducing the mask base body 12. By virtue of the aperture in theperipheral bead 23 in the region of the respective strap loops, it ispossible for the strap loops to be injection molded integrally with themask base body 12, without the need for sliding mold portions in thatrespect.

In the embodiment of the mask base body 12 diagrammatically illustratedhere, provided in parallel with a respiratory gas passage 24 is asecondary passage 25 by way of which for example pressure measurementcan be effected, without reductions in cross-section occurring in thatcase.

The tool here is of a three-part construction and includes an upper moldhalf 26, a lower mold half 27 and a sliding mold portion 28 which can bewithdrawn in the direction r3 from the respiratory gas passage 24.

Although the invention has been described hereinbefore with reference topreferred embodiments in which there is a single fold indentation whichdoes not extend around the entire periphery of the mask pad, theinvention is not limited to embodiments of that kind.

For example it is possible for the bellows structure to be provided witha plurality of fold indentations, of which possibly one or more extendaround the entire periphery of the mask pad.

An example of a corresponding cross-sectional configuration is shown inFIG. 10. The mask pad 1 which is here fixed to a mask base body 12 whichis only indicated in respect of a portion thereof, by way of aperipheral bead structure of a crochet needle-like cross-section, hastwo local fold indentations 39, 49. The wall of those local foldindentations 39, 49 is matched in regard to a defined hinge andflexibility characteristic.

In this embodiment the sealing lip 3 is of a comparatively thick-wallnature. That cross-section is suitable in particular for silicone rubbermaterial with an extremely low Shore hardness.

The breathing mask shown in FIG. 11 includes a mask base body 12 whichis made from a preferably fully transparent thermoplastic material.Provided in a wall portion which in the application position of the maskis adjacent to the forehead region of the mask wearer is a connectingportion 60 which here is of a polygonal cross-section.

The sealing pad device 3 is fixed to the mask base body 12 by way of aperipheral bead structure (not visible here). The sealing pad device 3has a bellows structure which extends locally from the upper end regionto an adaptation axis A. Provided in the region of the adaptation axis Aon both sides of the sealing pad are zones of higher load-bearingcapability which are formed by thicker-walled, spherically curved zonesof the sealing pad device.

For the purposes of fitting the breathing mask to the face of a maskwearer, provided at both sides of the mask are fixing devices 61, by wayof which a head band 61 a can be coupled to the breathing mask.

On its top side the mask body 12 is provided with a projection 62 bywhich the mask body generally is stiffened, thereby affording animproved characteristic in terms of sound conduction through solids.

Also provided in the region of the top side of the mask body 12 are aplurality of outlet openings 63, 64, by way of which a low-noise,directed discharge flow of partially consumed respiratory air can occurfrom the interior (or plenum chamber) of the mask. The discharge of thatleakage gas flow is promoted by a break-away edge 65 of a spoiler-likeconfiguration. The openings 64 direct the flow substantially in thedirection indicated by the arrow P1. The openings 63 which are alsoprovided on the opposite side (not visible here) of the projection 62open in the directions P2 and P3.

FIG. 12 shows the breathing mask of FIG. 11 from a direction of viewwhich is directed inclinedly from below onto the zone 4 of highload-bearing capability. It is also possible to see here, beside thelocal bellows structure 9, the region of the sealing lip 3 which bearsagainst the face of the mask wearer. In the region of the zone a themask is distinguished by a high level of adaptability to different nosebridge heights. In the zones b1 and b2 the mask pad 1 is supported in adefined manner against the face of the mask wearer. In the region c onceagain there is a higher level of flexibility and a higher degree ofadaptability to different upper lip contours.

The mask pad is of such a design configuration that there is a relief ofload in the region of the zones b1 and b2, as a consequence of theinternal pressure in the mask which occurs in the context ofover-pressure artificial respiration. The surface pressure of the maskpad in the region of the zones a and c is substantially determined bythe internal pressure in the mask. In the peripheral direction thesealing pad 1 has a high level of radial stiffness whereby the tendencyto oscillation of the sealing pad in relation to alternating artificialrespiration pressures is markedly reduced.

FIG. 13 is a greatly simplified view in section through the region ofthe sealing lip device 3, which fits on the upper lip 70 of a maskwearer. In a transitional region from the sealing pad device into thehard shell body 12, the configuration of the cross-sections of thesealing pad device 3 and the hard shell body 12 is such that there is asubstantially smooth transition in respect of the respective internalsurfaces. That ensures a favorable flow path directly in the region ofthe nostrils of the mask wearer.

As indicated, in this case also there is a local bellows structure 66which ensures improved adaptability to different upper liparchitectures.

FIG. 14a shows a portion of the arrangement illustrating thetransitional region between the hard shell body 12 and the sealing paddevice 1. Formed directly in the sealing pad device 1 is a leakageopening 67 which is here of a cross-section which decreases in thedischarge direction. The cross-sections of that leakage opening 67 arepreferably of the configuration diagrammatically shown in FIG. 15.

FIG. 14b shows a further embodiment of a leakage opening 68 which isintegrated into the sealing pad device 1. In the embodiment illustratedhere a wall formed by the hard shell body 12 extends into the flow path.This embodiment can be cleaned in a particularly advantageous manner asthe flow path is exposed over a large area after removal of the sealingpad device 1 from the hard shell body 12. Illustrated FIG. 14f is a viewof a detail of that sealing pad, in the direction of view identified asx1. As can be seen therein the peripheral bead 12 a of the hard shellbody 12 extends partially into the recess 69 formed in the cushion paddevice 1.

In the embodiment shown in FIG. 14c , provided in the region of thejoint between the hard shell body 12 and the sealing pad device 1 in thehard shell body is a channel portion 76 by way of which there can be adischarge flow of gas, as indicated by dash-dotted lines. The exitregion of the channel portion 76, as illustrated, opens into an outletpassage 71 which is defined jointly by the sealing pad device 3 and thehard shell body 12.

In the embodiment shown in FIG. 14d , provided in the hard shell body 12is at least one outlet passage 72 which goes into an aligned dischargepassage 73 in the sealing device 1.

FIG. 14e shows an embodiment of a leakage device in which a wall portion74 which is integral with the sealing pad device 1 is taken from theinterior (or plenum chamber) to an outlet opening region 75 of the hardshell body 12. That wall portion 74 is here provided with an outletopening 67 which tapers conically in the discharge direction and whichis arranged coaxially with respect to a preferably considerably largeroutlet opening 75 a.

The flow paths described with reference to FIGS. 14a through 14e arepreferably of at least one of the cross-sections 78-84 diagrammaticallyshown in FIGS. 15a -15 d.

FIG. 16 indicates a preferred location for providing the discharge flowopenings which are provided jointly with the sealing pad device 1 oralso separately therefrom. Preferably the discharge flow occurs in theregion of the zone c in combination with the zones b1 and b2, butpreferably larger volume flows are admitted in the region c.

While the invention has been described in connection with what ispresently considered to be the most practical and preferred embodiment,it is to be understood that the invention is not to be limited to thedisclosed embodiment, but on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

1. An elastomeric cushion for a breathing mask configured for sealeddelivery of a flow of breathable gas at a positive pressure with respectto ambient air pressure to an entrance of a patient's airways includingat least an entrance of the patient's nares, the elastomeric cushionhaving zones of differing load-bearing capability, wherein a first zoneincludes a zenith of the cushion, a second zone is positioned oppositethe first zone and a pair of intermediate zones extend between the firstand second zones, the elastomeric cushion comprising: a peripherallyextending shell engaging portion configured to secure the elastomericcushion to a shell of the breathing mask; a peripheral wall extendingfrom the shell engaging portion and defining a plenum chamber, a portionof the peripheral wall in the first zone being more collapsible thatportions of the peripheral wall in the second zone and the intermediatezones so that the cushion is pivotable around an axis that is betweenthe first zone and the second zone and extends through the pair ofintermediate zones; and an engagement surface defining an opening to thebreathing chamber and being configured to engage the patient's face, theperipheral wall extending from the shell engaging portion to theengagement surface, wherein portions of the engagement surface in thefirst zone and the second zone have a relatively thin elastomeric wallcompared to elastomeric walls of the portions of the elastomeric surfacein the pair of intermediate zones.
 2. The elastomeric cushion of claim1, wherein the portion of the engagement surface in the first zone isconfigured to engage a bridge of the patient's nose.
 3. The elastomericcushion of claim 1, wherein the shell engaging portion is configured tobe secured to the shell of the breathing mask by way of a projection andgroove system, the projection and groove system comprising a pluralityof projections interlocking with a plurality of receiving grooves arounda periphery of the shell and a periphery of the cushion.
 4. Theelastomeric cushion of claim 1, wherein the portion of the peripheralwall in the first zone comprises a bellows structure.
 5. The elastomericcushion of claim 1, wherein the portion of the engagement surface in thesecond zone is configured to engage the patient's upper lip or a regionbetween the patient's nose and upper lip.
 6. The elastomeric cushion ofclaim 1, wherein a cross-section of the elastomeric walls of theperipheral wall taken along a line from the shell engaging portion tothe engagement surface has a varied thickness.
 7. The elastomericcushion of claim 1, wherein the portion of the engagement surface in thefirst zone is configured to engage a bridge of the patient's nose,wherein the shell engaging portion is configured to be secured to theshell of the breathing mask by way of a projection and groove system,the projection and groove system comprising a plurality of projectionsinterlocking with a plurality of receiving grooves around a periphery ofthe shell and a periphery of the cushion, wherein the portion of theperipheral wall in the first zone comprises a bellows structure, whereinthe portion of the engagement surface in the second zone is configuredto engage the patient's upper lip or a region between the patient's noseand upper lip, and wherein a cross-section of the elastomeric walls ofthe peripheral wall taken along a line from the shell engaging portionto the engagement surface has a varied thickness.
 8. A patient interfacefor sealed delivery of a flow of breathable gas at a positive pressurewith respect to ambient air pressure to an entrance to the patient'sairways including at least an entrance of a patient's nares, saidpatient interface comprising: the elastomeric cushion of claim 1; thepatient interface shell configured to be secured to the shell engagingportion of the elastomeric cushion, the patient interface comprising acentral aperture adapted to receive the flow of breathable gas; andheadgear configured to support the patient interface on the patient'shead and maintain the elastomeric cushion in sealing contact with anarea surrounding an entrance to the patient's airways while maintaininga therapeutic pressure at the entrance to the patient's airways.
 9. Thepatient interface of claim 8, wherein the plenum chamber is defined bythe patient interface shell in conjunction with the peripheral wall ofthe elastomeric cushion, and the plenum chamber is pressurized at apressure above ambient pressure.
 10. The patient interface of claim 8,further comprising a gas washout vent located on the patient interfaceshell, and wherein the patient interface shell is comprised of a hardand transparent material.
 11. An elastomeric cushion for a breathingmask configured for sealed delivery of a flow of breathable gas at apositive pressure with respect to ambient air pressure to an entrance ofa patient's airways including at least an entrance of the patient'snares, the elastomeric cushion being configured to form a seal with thepatient's face and comprising: a first zone comprising a portion of anelastomeric wall configured to sealingly engage a bridge of thepatient's nose; a second zone comprising a second portion of theelastomeric wall configured to sealingly engage the patient's face at alocation opposite the first zone; and a pair of intermediate zonescomprising portions of the elastomeric wall configured to sealinglyengage the patient's face between the first and second zones, whereinthe portions of the elastomeric wall in the first zone, the second zoneand the pair of intermediate zones are configured so that portions ofthe seal in the first and second zone are formed by relatively thinelastomeric walls and portions of the seal in the pair of intermediatezones are formed by relatively thick elastomeric walls.
 12. Theelastomeric cushion of claim 11, wherein the relatively thick portionsof the elastomeric wall in the pair of intermediate zones has a higherload bearing capability than the relatively thin portions of theelastomeric wall in the first and second zones.
 13. The elastomericcushion of claim 11 further comprising a bellows structure overlappingthe first zone and configured to increase a degree of flexibility of theportion of the elastomeric wall in the first zone.
 14. The elastomericcushion of claim 13, wherein the bellows structure overlaps portions ofthe intermediate zones.
 15. The elastomeric cushion of claim 11, whereinthe first zone, the second zone and the pair of intermediate zonestogether define an opening in the elastomeric cushion.
 16. A patientinterface for sealed delivery of a flow of breathable gas at a positivepressure with respect to ambient air pressure to an entrance to thepatient's airways including at least an entrance of a patient's nares,said patient interface comprising: a patient interface shell with acentral aperture adapted to receive the flow of breathable gas; theelastomeric cushion of claim 11; and a plenum chamber defined by theelastomeric cushion and the patient interface shell, the plenum chamberbeing pressurized at a pressure above ambient pressure.
 17. The patientinterface of claim 16, wherein the elastomeric cushion and the patientinterface shell are secured together by a projection and groove system,the projection and groove system comprising a plurality of projectionsinterlocking with a plurality of receiving grooves around a periphery ofthe shell and a periphery of the cushion.
 18. The patient interface ofclaim 17 further comprising headgear configured to support the patientinterface on the patient's head and maintain the elastomeric cushion insealing contact with an area surrounding an entrance to the patient'sairways while maintaining a therapeutic pressure at the entrance to thepatient's airways.
 19. The patient interface of claim 18, furthercomprising a gas washout vent located on the patient interface shell.20. The patient interface of claim 19, wherein the shell is comprised ofa hard and transparent material.
 21. An elastomeric cushion for abreathing mask configured for sealed delivery of a flow of breathablegas at a positive pressure with respect to ambient air pressure to anentrance of a patient's airways including at least an entrance of thepatient's nares, the elastomeric cushion comprising: a sealing lip withan elastomeric wall configured to form a seal with the patient's face,an elastomeric wall thickness of the sealing lip being varied so thatwhen the sealing lip sealingly engages the patient's face, a portion ofthe seal at the patient's nose bridge is formed by a relativelythin-walled portion of the sealing lip and other portions of the sealare formed by relatively thick portions of the sealing lip.
 22. Theelastomeric cushion of claim 21 further comprising: a peripherallyextending shell engaging portion configured to secure the elastomericcushion to a shell of the breathing mask; and an intervening portionbetween the shell engaging portion and the sealing lip, the interveningportion comprising a bellows structure configured to increase a degreeof flexibility of a nasal bridge engaging portion of the elastomericcushion.
 23. The elastomeric cushion of claim 22, wherein the bellowsstructure is positioned between a nose bridge engaging portion of thesealing lip and the shell engaging portion.
 24. The elastomeric cushionof claim 23, wherein a portion of the bellows structure extends beyondthe nose bridge engaging portion of the sealing lip.
 25. The elastomericcushion of claim 24, wherein an elastomeric wall thickness of the nasalbridge engaging portion of the elastomeric cushion varies from the shellengaging portion to the sealing lip to form an elastomeric thin-wallportion adjacent a hinge of the bellows structure that promotes a hingedmotion around the hinge.
 26. A patient interface for sealed delivery ofa flow of breathable gas at a positive pressure with respect to ambientair pressure to an entrance to the patient's airways including at leastan entrance of a patient's nares, said patient interface comprising: apatient interface shell with a central aperture adapted to receive theflow of breathable gas; the elastomeric cushion of claim 21; and aplenum chamber defined by the elastomeric cushion and the patientinterface shell, the plenum chamber being pressurized at a pressureabove ambient pressure.
 27. The patient interface of claim 26 furthercomprising headgear configured to support the patient interface on thepatient's head and maintain the elastomeric cushion in sealing contactwith an area surrounding an entrance to the patient's airways whilemaintaining a therapeutic pressure at the entrance to the patient'sairways.
 28. The patient interface of claim 27, further comprising a gaswashout vent located on the shell.
 29. The patient interface of claim28, wherein the shell is comprised of a hard and transparent material.30. The elastomeric cushion of claim 22, wherein a cross-section ofelastomeric walls of the peripheral wall taken along a line from theshell engaging portion to sealing lip has a varied thickness.